In typical data processing systems, a compiler reads source code and creates the object code which is ultimately processed. Typically, the compiler creates a data structure which will support property values which are defined later in the source code or during run time. In an object oriented system, the compiler may create a class and a mechanism for creating instances of that class with defined fields of preallocated memory space into which the values are stored.
Such a data structure has, for example, been supported in the [incr Tk] language, which allows values to be stored in strings or arrays as options associated with an instance object.